Use jest

.babelrc.js

@@ -1,9 +1,20 @@
 "use strict";
 
-let envOpts = {
+const env = process.env.BABEL_ENV || process.env.NODE_ENV;
+const envOpts = {
   loose: true,
 };
 
+switch(env) {
+  case "development":
+    envOpts.debug = true;
+    // fall-through
+  case "test":
+    envOpts.targets = {
+      node: "current"
+  };
+}
+
 const config = {
   comments: false,
   presets: [["@babel/env", envOpts]],
@@ -27,16 +38,10 @@ const config = {
   ],
 };
 
+// we need to do this as long as we do not test everything from source
 if (process.env.BABEL_ENV === "cov") {
   config.auxiliaryCommentBefore = "istanbul ignore next";
   config.plugins.push("babel-plugin-istanbul");
 }
 
-if (process.env.BABEL_ENV === "development") {
-  envOpts.targets = {
-    node: "current",
-  };
-  envOpts.debug = true;
-}
-
 module.exports = config;

.circleci/config.yml

@@ -51,8 +51,8 @@ jobs:
       # test-ci-coverage doesn't test babel-standalone, as trying to gather coverage
       # data for a JS file that's several megabytes large is bound to fail. Here,
       # we just run the babel-standalone test separately.
-      - run: ./node_modules/mocha/bin/_mocha packages/babel-standalone/test/ --opts test/mocha.opts
-      - run: ./node_modules/mocha/bin/_mocha packages/babel-preset-env-standalone/test/ --opts test/mocha.opts
+      - run: ./node_modules/.bin/jest packages/babel-standalone/test/
+      - run: ./node_modules/.bin/jest packages/babel-preset-env-standalone/test/
       - store_artifacts: *artifact_babel
       - store_artifacts: *artifact_babel_min
       - store_artifacts: *artifact_env

.eslintrc

@@ -28,7 +28,7 @@
         "test/**/*.js"
       ],
       "env": {
-        "mocha": true
+        "jest": true
       }
     }
   ]

.travis.yml

@@ -7,6 +7,7 @@ cache:
   directories:
   - node_modules
 node_js:
+  - '9'
   - '8'
   - '6'
   - '4'
@@ -19,6 +20,8 @@ env:
 before_install:
   - curl -o- -L https://yarnpkg.com/install.sh | bash
 
+install: yarn --ignore-engines
+
 before_script:
   - 'if [ "$JOB" = "babylon-flow-tests" ]; then make bootstrap-flow; fi'
   - 'if [ "$JOB" = "babylon-test262-tests" ]; then make bootstrap-test262; fi'

Makefile

@@ -81,7 +81,7 @@ test-ci:
 test-ci-coverage: SHELL:=/bin/bash
 test-ci-coverage:
 	BABEL_ENV=cov make bootstrap
-	./scripts/test-cov.sh
+	TEST_TYPE=cov ./scripts/test-cov.sh
 	bash <(curl -s https://codecov.io/bash) -f coverage/coverage-final.json
 
 bootstrap-flow:
@@ -130,8 +130,8 @@ publish:
 
 bootstrap:
 	make clean-all
-	yarn
-	./node_modules/.bin/lerna bootstrap
+	yarn --ignore-engines
+	./node_modules/.bin/lerna bootstrap -- --ignore-engines
 	make build
 	cd packages/babel-runtime; \
 	node scripts/build-dist.js

package.json

@@ -16,9 +16,10 @@
     "@babel/preset-flow": "7.0.0-beta.40",
     "@babel/preset-stage-0": "7.0.0-beta.40",
     "@babel/register": "7.0.0-beta.40",
+    "babel-core": "^7.0.0-0",
     "babel-eslint": "^8.0.1",
+    "babel-jest": "^22.4.1",
     "babel-loader": "8.0.0-beta.0",
-    "babel-plugin-istanbul": "^4.1.5",
     "babel-plugin-transform-charcodes": "^0.1.0",
     "babylon": "7.0.0-beta.40",
     "browserify": "^13.1.1",
@@ -44,13 +45,12 @@
     "gulp-util": "^3.0.7",
     "gulp-watch": "^4.3.5",
     "husky": "^0.14.3",
+    "jest": "^22.4.2",
     "lerna": "2.0.0",
     "lerna-changelog": "^0.5.0",
     "lint-staged": "^6.0.1",
     "lodash": "^4.2.0",
     "merge-stream": "^1.0.1",
-    "mocha": "^3.0.0",
-    "nyc": "^11.0.3",
     "output-file-sync": "^2.0.0",
     "prettier": "1.10.2",
     "pump": "^1.0.2",
@@ -71,20 +71,44 @@
     "npm": ">= 2.x <= 5.x",
     "yarn": ">=0.27.5 || >=1.0.0-20170811"
   },
-  "nyc": {
-    "all": true,
-    "exclude": [
-      "scripts/*.js",
-      "packages/*/test/**",
-      "packages/babel-standalone/**",
-      "codemods/*/test/**"
-    ],
-    "sourceMap": false,
-    "instrument": false
-  },
   "lint-staged": {
     "*.js": [
       "eslint --format=codeframe --rulesdir='./scripts/eslint_rules'"
     ]
+  },
+  "jest": {
+    "collectCoverageFrom": [
+      "packages/*/src/**/*.js",
+      "codemods/*/src/**/*.js"
+    ],
+    "testRegex": "./(packages|codemods)/[^/]+/test/.+\\.js$",
+    "testPathIgnorePatterns": [
+      "/node_modules/",
+      "/test/fixtures/",
+      "/test/debug-fixtures/",
+      "/babylon/test/expressions/",
+      "/test/tmp/",
+      "/test/__data__/",
+      "/test/helpers/",
+      "<rootDir>/test/warning.js",
+      "<rootDir>/build/",
+      "_browser.js"
+    ],
+    "testEnvironment": "node",
+    "setupTestFrameworkScriptFile": "<rootDir>/test/testSetupFile.js",
+    "transformIgnorePatterns": [
+      "/node_modules/",
+      "/test/fixtures/",
+      "/test/tmp/",
+      "/test/__data__/",
+      "/lib/"
+    ],
+    "modulePaths": [
+      "<rootDir>/packages/"
+    ],
+    "modulePathIgnorePatterns": [
+      "/test/fixtures/",
+      "<rootDir>/build/"
+    ]
   }
 }

packages/babel-cli/test/index.js

@@ -122,7 +122,13 @@ const buildTest = function(binName, testName, opts) {
   const binLoc = path.join(__dirname, "../lib", binName);
 
   return function(callback) {
-    clear();
+    const dir = process.cwd();
+
+    process.chdir(__dirname);
+    if (fs.existsSync(tmpLoc)) rimraf.sync(tmpLoc);
+    fs.mkdirSync(tmpLoc);
+    process.chdir(tmpLoc);
+
     saveInFiles(opts.inFiles);
 
     let args = [binLoc];
@@ -160,6 +166,7 @@ const buildTest = function(binName, testName, opts) {
           args.map(arg => `"${arg}"`).join(" ") + ": " + err.message;
       }
 
+      process.chdir(dir);
       callback(err);
     });
 
@@ -170,13 +177,6 @@ const buildTest = function(binName, testName, opts) {
   };
 };
 
-const clear = function() {
-  process.chdir(__dirname);
-  if (fs.existsSync(tmpLoc)) rimraf.sync(tmpLoc);
-  fs.mkdirSync(tmpLoc);
-  process.chdir(tmpLoc);
-};
-
 fs.readdirSync(fixtureLoc).forEach(function(binName) {
   if (binName[0] === ".") return;
 

packages/babel-code-frame/src/index.js

@@ -180,15 +180,17 @@ export default function(
   if (!deprecationWarningShown) {
     deprecationWarningShown = true;
 
-    const deprecationError = new Error(
-      "Passing lineNumber and colNumber is deprecated to @babel/code-frame. Please use `codeFrameColumns`.",
-    );
-    deprecationError.name = "DeprecationWarning";
+    const message =
+      "Passing lineNumber and colNumber is deprecated to @babel/code-frame. Please use `codeFrameColumns`.";
 
     if (process.emitWarning) {
-      process.emitWarning(deprecationError);
+      // A string is directly supplied to emitWarning, because when supplying an
+      // Error object node throws in the tests because of different contexts
+      process.emitWarning(message, "DeprecationWarning");
     } else {
-      console.warn(deprecationError);
+      const deprecationError = new Error(message);
+      deprecationError.name = "DeprecationWarning";
+      console.warn(new Error(message));
     }
   }
 

packages/babel-core/test/api.js

@@ -299,6 +299,9 @@ describe("api", function() {
       return { plugins: [pushPlugin(str)] };
     }
 
+    const oldEnv = process.env.BABEL_ENV;
+    process.env.BABEL_ENV = "development";
+
     const result = babel.transform("", {
       filename: path.join(
         __dirname,
@@ -316,6 +319,12 @@ describe("api", function() {
       },
     });
 
+    if (oldEnv === undefined) {
+      delete process.env.BABEL_ENV;
+    } else {
+      process.env.BABEL_ENV = oldEnv;
+    }
+
     assert.equal(
       result.code,
       [
@@ -535,14 +544,14 @@ describe("api", function() {
     const oldBabelEnv = process.env.BABEL_ENV;
     const oldNodeEnv = process.env.NODE_ENV;
 
-    setup(function() {
+    beforeEach(function() {
       // Tests need to run with the default and specific values for these. They
       // need to be cleared for each test.
       delete process.env.BABEL_ENV;
       delete process.env.NODE_ENV;
     });
 
-    suiteTeardown(function() {
+    afterAll(function() {
       process.env.BABEL_ENV = oldBabelEnv;
       process.env.NODE_ENV = oldNodeEnv;
     });

packages/babel-core/test/config-chain.js

@@ -844,6 +844,19 @@ describe("buildConfigChain", function() {
       plugins: [],
       presets: [],
     });
+    const realEnv = process.env.NODE_ENV;
+    const realBabelEnv = process.env.BABEL_ENV;
+
+    beforeAll(() => {
+      delete process.env.NODE_ENV;
+      delete process.env.BABEL_ENV;
+    });
+    afterAll(() => {
+      if (realEnv) {
+        process.env.NODE_ENV = realEnv;
+        process.env.NODE_ENV = realBabelEnv;
+      }
+    });
 
     it("should load .babelrc", () => {
       const filename = fixture("config-files", "babelrc", "src.js");

packages/babel-core/test/resolution.js

@@ -4,14 +4,15 @@ import path from "path";
 
 describe("addon resolution", function() {
   const base = path.join(__dirname, "fixtures", "resolution");
+  let cwd;
 
   beforeEach(function() {
-    this.cwd = process.cwd();
+    cwd = process.cwd();
     process.chdir(base);
   });
 
   afterEach(function() {
-    process.chdir(this.cwd);
+    process.chdir(cwd);
   });
 
   it("should find module: presets", function() {

packages/babel-helper-transform-fixture-test-runner/package.json

@@ -13,6 +13,7 @@
     "@babel/helper-fixtures": "7.0.0-beta.40",
     "@babel/polyfill": "7.0.0-beta.40",
     "chai": "^4.1.0",
+    "jest": "^22.4.2",
     "lodash": "^4.2.0",
     "resolve": "^1.3.2",
     "source-map": "^0.5.0"

packages/babel-helper-transform-fixture-test-runner/src/index.js

@@ -1,4 +1,4 @@
-/* eslint-env mocha */
+/* eslint-env jest */
 import * as babel from "@babel/core";
 import { buildExternalHelpers } from "@babel/core";
 import getFixtures from "@babel/helper-fixtures";
@@ -11,7 +11,6 @@ import extend from "lodash/extend";
 import merge from "lodash/merge";
 import resolve from "resolve";
 import assert from "assert";
-import chai from "chai";
 import fs from "fs";
 import path from "path";
 import vm from "vm";
@@ -321,7 +320,7 @@ function checkDuplicatedNodes(ast) {
 
 function run(task) {
   const actual = task.actual;
-  const expect = task.expect;
+  const expected = task.expect;
   const exec = task.exec;
   const opts = task.options;
   const optionsDir = task.optionsDir;
@@ -376,29 +375,27 @@ function run(task) {
   }
 
   let actualCode = actual.code;
-  const expectCode = expect.code;
+  const expectCode = expected.code;
   if (!execCode || actualCode) {
     result = babel.transform(actualCode, getOpts(actual));
     checkDuplicatedNodes(result.ast);
     if (
-      !expect.code &&
+      !expected.code &&
       result.code &&
       !opts.throws &&
-      fs.statSync(path.dirname(expect.loc)).isDirectory() &&
+      fs.statSync(path.dirname(expected.loc)).isDirectory() &&
       !process.env.CI
     ) {
-      console.log(`New test file created: ${expect.loc}`);
-      fs.writeFileSync(expect.loc, `${result.code}\n`);
+      console.log(`New test file created: ${expected.loc}`);
+      fs.writeFileSync(expected.loc, `${result.code}\n`);
     } else {
       actualCode = result.code.trim();
-      chai
-        .expect(actualCode)
-        .to.be.equal(expectCode, actual.loc + " !== " + expect.loc);
+      expect(actualCode).toEqual(expectCode);
     }
   }
 
   if (task.sourceMap) {
-    chai.expect(result.map).to.deep.equal(task.sourceMap);
+    expect(result.map).toEqual(task.sourceMap);
   }
 
   if (task.sourceMappings) {
@@ -407,10 +404,8 @@ function run(task) {
     task.sourceMappings.forEach(function(mapping) {
       const actual = mapping.original;
 
-      const expect = consumer.originalPositionFor(mapping.generated);
-      chai
-        .expect({ line: expect.line, column: expect.column })
-        .to.deep.equal(actual);
+      const expected = consumer.originalPositionFor(mapping.generated);
+      expect({ line: expected.line, column: expected.column }).toEqual(actual);
     });
   }